1. Field of the Invention
The present invention relates to a connecting arrangement for establishing a torque-transmitting connection between an input drive such as a crankshaft and a hydrodynamic coupling device.
2. Description of the Related Art
A connecting arrangement for connecting a torque converter to an input drive shaft is disclosed in German reference DE 32 22 119 C1 in which a radially inner area of a flexible transmission plate is screwed to the input drive shaft and a radially outer area of the flexible transmission plate is screwed to the housing of the torque converter or to fastening portions provided thereon. The flexible transmission plate is used to establish a torque-transmitting connection between the input drive shaft and the torque converter and to ensure that slight inaccuracies in the positioning of the input drive shaft relative to a gearbox input shaft during rotational operation are compensated for by virtue of the flexibility of this plate.
Flexible transmission plates of this kind are typically fixed to the input drive shaft and the torque converter by axial screwing to establish torque transmission which is in principle capable of meeting the torque transmission requirements which arise in operation. A problem with this connection arrangement is that as motor vehicle designs are becoming more and more dense, access to the screws provided for fastening the flexible transmission plates is becoming more and more limited. This limited access increases the difficulty in connecting the flexible plates and therefore increases assembly complexity and cost.
It is the object of the present invention to provide a connecting arrangement for connecting a coupling device such as a hydrodynamic torque converter to an input drive so that it is possible to compensate for misalignments of various component of a motor vehicle drive system during torque transmission. It is a further object of the present invention to provide a connecting arrangement that is simple to construct and a connection which is simple to establish.
According to the invention, this object is achieved by a connecting arrangement for establishing a torque-transmitting connection between an input drive and a coupling device, the connecting arrangement comprising a transmission element which is connectable to the input drive. A first engagement formation is arranged on the transmission element which is in a torque-transmitting engagement with a second engagement formation which is attached to the coupling device. An engagement/retention arrangement is operatively connected to act between the transmission element and the coupling device for holding the first and the second engagement formation in torque-transmitting engagement once torque-transmitting engagement has been established between the first and the second engagement formation.
The connecting arrangement according to the present invention comprises a flexible design and is not attached to the coupling device by introducing bolts or the like. Instead, the connection is produced by interengaging first and second engagement formations which fundamentally assume the torque transmission function. These first and second engagement formations provide coupling in terms of force, preferably form-fitting coupling, about the axis of rotation of the system in the circumferential direction. The engagement/retention arrangement ensures that the coupling state is maintained while torques are transmitted during operation by preventing these first and second engagement formations from decoupling. It should be pointed out that where reference is made in the present text to the fact that the engagement/ retention arrangement acts between two components, this does not mean that the engagement/retention arrangement has to engage directly on these two components. For example, it is possible for there to be intermediate members which ultimately provide the connection between the engagement/retention arrangement and the components discussed.
In a preferred embodiment, the transmission element may comprise a plate-type design, wherein a radially inner area of the transmission element is designed for connection to the input drive. In this embodiment, the first engagement formation is arranged radially to the outside of the connection to the input drive.
A coupling which is very reliable and is suitable for transmitting high torques may be obtained if the first engagement formation comprises a first toothing formation and the second engagement formation comprises a complementary second toothing formation.
To simultaneously provide the function of centering the coupling device relative to the input drive by the first and second toothing formations for establishing torque coupling, it is proposed that the first and the second toothing formation each form an axial toothing, preferably in the form of a Hirth toothing. The first and second toothing formations are arranged such that as the two toothing formations are brought into engagement, the input drive and the coupling device are forcibly aligned.
To achieve the required flexibility of the connecting arrangement, the transmission element comprises a plurality of transmission arms which extend radially outwards. At least part of the first engagement formation is provided on at least some of the transmission arms.
To maintain torque-transmitting engagement between the first and the second engagement formations once established, it is proposed that the engagement/retention arrangement comprises a retention element arranged on the coupling device such that it is rotatable about an axis of rotation. The retention element is supported in the axial direction and has a third engagement formation. The transmission element has a retention area with a fourth engagement formation, which may be brought into or out of retaining engagement with the third engagement formation by rotating the retention element about the axis of rotation.
The third and the fourth engagement formations may, for example, be made of a thread-type design. All that occurs then is that the retention element is brought into engagement with the retention area of the transmission element by rotation about the axis of rotation in the manner of a screw or a nut, thereby producing an engagement which acts in a form-fitting manner in the axial direction and essentially prevents or limits the axial movement of the transmission element. The result of the engagement of the retention element and the retention area is that the first engagement formation is forcibly held in torque-transmitting engagement with the second engagement formation.
For example, the retention element may comprise a sleeve-type design with a thread configuration on its circumferential surface as a third engagement formation. To provide axial support for the retention element, a retaining-projection area is arranged on the retention element. The retaining-projection area is supported axially against a counterretaining-projection area attached to the coupling device or another component.
Once the torque-transmitting state has been established, it is advantageous to ensure that the coupling state is not canceled by unwanted release of the retention element. Therefore, the retention element may be locked against rotation about the axis of rotation. An arrangement for locking the retention element against rotation may, for example, comprise separate locking elements. However, the arrangement for locking the retention element may also comprise a design of the third and fourth engagement formations as a thread acting in a self-locking manner.
To provide the configuration which maintains the torque-coupling state, an essentially axially extending area may be provided on the transmission element with the fourth engagement formation on a circumferential surface of the axially extending area. In a preferred embodiment, the essentially axially extending retention portion, on which at least part of the fourth engagement formation is provided, may be arranged on the radially outer area of at least some of the transmission arms.
The connecting arrangement according to the invention may be produced in a simple and very economical manner if the transmission element comprises a formed sheet-metal part. In this case, the material properties of sheet-metal parts simultaneously ensure the required or desired flexibility of the transmission element.
The present invention furthermore relates to the combination of a coupling device, in particular a hydrodynamic coupling device, with a connecting arrangement according to the invention.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.